Emily Rogers reports: The impact of a fifth terminal at Heathrow fuelled a debate attended by London's four main mayoral candidates.

At London's Great Transport Debate, held earlier this month and sponsored by the British Airports Authority (BAA), mayoral hopefuls Frank Dobson, Susan Kramer, Ken Livingstone and Steven Norris were asked to comment on BAA's admission that if built, the new terminal would create nearly 50,000 extra car trips a day across London.

'If the Government gives the go ahead for Terminal 5 the Mayor is going to have to clean up the mess,' said Mr Livingstone, who is standing as an independent.

Liberal Democrat candidate Susan Kramer said she was opposed to Terminal 5, which she said would be a second airport rather than just another terminal. 'The impact on the roads is going to be phenomenal. There's a lot we can do without expansion.'

Labour candidate Frank Dobson and Conservative hopeful Steve Norris both acknowledged that an expansion of the airport would create major problems that would have to be addressed by the new mayor.

BAA spokeswoman Emma Gaisford said the estimated 50,000 extra car trips a day created by T5 had to be seen in context of the total number of vehicles on the same roads which have nothing to do with the terminal.

'This figure is in the region of 1.5æmillion car trips per day, showing that Terminal 5 would be specifically responsible for only three per cent of cars on the roads,' she said. At the beginning of February, Hillingdon Council and west London Friends of the Earth condemned Heathrow's passenger figures for the end of 1999 which showed the total was half a million higher than predicted.

They called into question Heathrow's projections during the four-year public inquiry which ended last year, of 80æ million passengers by 2016, claiming the figure would be nearer 100æmillion a year, which would put much more pressure on the environment and quality of life around the airport. The Government's planning inspector will make a recommendation on the issue later this year.